Thanks, Merc888, for sharing your detailed tests. It confirms for the n-th time that if your car is spec-ed to RON 95, don’t waste money on 98.
One must also not discount the possibility of placebo effect. Because if you pump 98, you will expect it to be more responsive and hence you go gentler on the paddle, and thereby saving fuel. I’m not saying in Merc888’s study that’s the case. His study is pretty comprehensive. But I have known people who succumb to placebo. A much fairer test would be to go blind pumping. Ask your wife or friend to pump for you, without them telling you what petrol they pumped.
But kudos for sharing an already great study with the W213 owners here! Thanks!

Hi! Glad you find the post helpful.
My parts are all original.
The original front lower grill comes in either black or with chrome trim. The chrome trim is not an add-on. However, if you are considering replica, then there are china chrome trims that you can buy to stick on. But I personally find them damn ugly.